ISIS/Alouette Topside Sounder Data Restoration

Background Information

Bob Benson (Goddard Space Flight Center, Code 692) is heading an effort
to convert Alouette and ISIS topside sounder data from the original
analog telemetry tapes into digital ionograms. A sample ISIS 2 digital
ionogram is shown at the top of this page. These sounders have produced
global mapping of the topside ionosphere over more than an
entire solar cycle. The National Space Science Data Center (NSSDC) has
more than 12,000 rolls of 35 mm microfilm containing Alouette 1,
Alouette 2, ISIS 1 and ISIS 2 topside ionograms. These data extend from
the launch of Alouette 1 in September, 1962 to March, 1983 and have
resulted in nearly 1,000 scientific publications. Not all of the data
during this time period were processed into ionograms. In addition,
most of the data extending from March, 1983 up to the turn-off of ISIS 1
& 2 in January, 1990 exist only on the original analog telemetry tapes
stored in Canada. Most of these tapes have now been destroyed because of
problems with media deterioration and the cost of tape storage.

The NASA Space Physics Data System (SPDS)-related Ionosphere,
Thermosphere, Mesosphere (ITM) Data Evaluation Panel has rated the
rescue and transformation of this data set as its highest priority
project. The full
ITM report is available here.